PHP Programming 101

Now, to make you a better programmer we all know the value of comments. This allows you to understand the code that you have written defining and given meaning to operations as you build them up. You start with the terminators used by PHP and end with them as well. Single line comments look like this �// comment� and Multi-line ones use the syntax /* comment comment*/. A better example would be the one below:

//comment
/* comment
Comment*/
?>

In the next post we take on the best parts of PHP which would be variables which is essential in all programming languages.

As you might have seen, all of the PHP statement ends with �;� which would be somewhat similar to Perl. The valid HTML code that was handed back to the server was :



Who are You?

My name is MacGyver.

More in the coming posts when we dig deeper as we widen our understanding of PHP.

The first post had you making a program that was equivalent to the “Hello World” program used for teaching basics of a programming language and here’s how it worked. When the script was requested by opening the web page, Apache intercepted the request and passed it onto PHP which parsed the script looking for the code in between the terminators and then doing the requested operation which was to display the text contained within the echo command. This result was given back to the server then again to the client. The output contained a valid HTML so the browser was able to understand it and execute the requested operation.

Several factors are to be considered should one be involved with deploying projects over the internet. One of the things you could do would be to have a nifty script that checks for the particular browser your clients might be using. This can be done with a simple and short piece of code that can mean the difference between a successful deployment without problems allowing proper extensions and plugins to be included. A sample of the code can be seen below for your reference which makes it easier for your program/web page to know which set of scripts and what parameters to adhere with. (more…)

Image sOurce:www.foundationphp.com
PHP was created by Rasmus Lerdorf in 1994 and it was written in C programming language. He created PHP so that he can trace the people who visited his online CV. To make things easier for him to debug his program, he made it into an open source. Then, on June 8, 1995, Lerdorf combined PHP and his own Form Interpreter because of the growing needs of web pages. It was now called as PHP/FI, but generally known as PHP 2.0. Then, in 1997, Andi Gutmans and Zeev Suraski rebuilt the main parser. Before Andi Gutmans and Zeec Suraski rewrote the PHP’s core, PHP was widely known as “Personal Homepage”.

PHP was widely known as “Personal Homepage” until Andi Gutsman and Zeev Suraski Rebuit the main parser of PHP. And so, the acronym PHP was formally changed to PERL Hypertext Preprocessor. Then PHP 3 was released in 1998.

PHP 4 was released in May 2000 with a new core known as the Zend Engine 1.0. In July 2004, PHP 5 was released with the updated Zend Engine 2.0 and new features. PHP 6 was released in October, 20006.

Arrays are what tables are to C-based programming languages and what databases are for SQL-based languages. Arrays or tables as they are sometimes called can be used to store the contents of several variables and to create one, you use the following syntax:

Array(key=>value)

The array in the syntax refers to the name of the array being created, the key is the index which is set automatically to a numeric character or string if none is specified. Value is the assigned value or content of the said array which can be seen easily in the following array creation example:

$b=array('z'=>‘Comedy”,’y'=>”Horror”,’x;’=>”Action”);
print_r($b);
?>

This piece of code would produce an output of :

Array ([0] => Comedy [1] => Horror [2] => Action)

More on array functions in the next posts.

The first step to get us on our way to programming in PHP would be to set up an ideal development environment. You need a Web Server software like Apache (which would be what we are going to use) which is only one of many out there. Most of these web servers are open-source meaning that they are free. Now, being free doesn�t mean that they are not up to standards for there are standards that are set by independent groups that are comprised of the many developers who together formulate or give a loosely defined set of standards for others to follow. Apache has versions for Linux but there are also for the Windows, Unix and Mac OS. The installer can be downloaded along with the detailed manual from PHP.net

(cont….)

V. Operators in PHP

*Arithmetic Operators*

+ addition
- subtraction
* multiplication
/ division
% modulus (division remainder)
++ increment
– decrement

*Comparison Operators*
== equal to
!= not equal
> greater than
= greater than or equal
<= less than or equal

*Logical Operators*
&& and
|| or
! not

I know its self explanatory…

VI. IF….Else Statements

If (condition)
//*Things to be executed if the answer to the condition is true*//
else
//*Things to be executed if the answer to the condition is false*//

If…else statement is use if the user wants to execute a set of code when the condition is true and another if the condition is not true.

VII. Switch Statement

switch (expression)
{
case 1:
//*code to be executed*//
break;
case 2:
//*code to be executed*//
break;
default:
//*code to be executed*//
break;
}

Switch statement is use if you want to select one of many blocks of code to be executed. this statement is used to avoid long blocks of if…elseif..else.

VIII. Looping Statement

while(condition)
code to be executed;

While statement is used to execute a block of code if and as long as a condition is true

do
{
code to be executed;
}while (condition)

Do—while statement is used to execute a block of code at least once and it will repeat the loop as long as the condition is true.

for each (array as value)
{
code to be executed;
}

For each statement is used to loop through arrays.

I think this is already enough and it has added new knowledge to those who are new in PHP… good luck and happy coding…

image source: www.cass.rrhosting.com

(cont…)
III. PHP Variables

$variablename=value;

Variables are used for storing values such as text string or arrays. And all variables in PHP starts with a ($) dollar sign. There are various rules to be follow before naming a variable. 1) A variable name must start with a letter or an underscore. 2) A variable name can only contain alpha-numeric characters and underscores. Special characters are not allowed. 3) A variable name should not contain spaces.

IV.PHP Strings

$wrd=”Hello World”;
print $wrd;

Strings variables are used for values that contain character strings. The only operator that can be used on string is concatenation denoted by the sign (.) period.

$wrd1=”Hello World”;
$wrd2=”Good day”;
print $wrd1.”".$wrd2

You can count the nos. of string with the function strlen().

Print strlen(“HelloWorld and GoodDay”);

to be continued…

image source: www.php-editors.com

Here are some of the basic things to be in mind while coding your dynamic web pages using PHP.

I. PHP basic syntax

PHP is a script that is place inside a HTML document that’s why you need to put the basic codes of HTML such as and .
PHP is open with the (?)question mark followed by “PHP” and closed with a (?) question mark.

II. Displaying in PHP

In order to display a text in PHP you need to use the keyword ECHO or PRINT. all code line ends with a semicolon.

To be continued…

image source: www.23hq.com